The invention relates to the application or discharge of media, particularly pharmaceutical products in atomized, jet or drop form and a dispenser for the same.
WO 96/24439 discloses a disposable dispenser, in which a glass ampoule sealed by a rubber plug and containing a liquid medium is inserted in a sleeve connected to a dispenser by means of a preset breaking connection. The dispenser has a projecting nose adapter with an atomizing nozzle at the end. A central shaft or member in the interior of said adapter carries in the centre a needle which, on actuation by a manual pressing of the sleeve into the adapter, perforates the rubber plug. The shaft then presses the rubber plug as a plunger into the ampoule and consequently produces the application pressure.
This disposable atomizer is very reliable and is eminently suitable for the application of liquid medicaments, particularly those which have to be rapidly absorbed by the body, e.g. by the nasal mucosa, whilst also avoiding incompatibilities for the digestive tract which can arise in the case of oral ingestion. However, there are medicaments, which are not stable for a long period in liquid form.
Although there are numerous proposals for powder application and dosing, this is problematical and only possible by whirling up in large air quantities. This eliminates many fields of application, because a planned application is scarcely possible in this way.
U.S. Pat. No. 3,756,390 relates to a hypodermic syringe, which has two chambers for liquid and powder separated from one another by a piercing foil. To the powder chamber is connected a connecting piece in which a needle can be inserted after removing a protective cap. After piercing the separating foil the two media are mixed together. The protective cap is then removed, the needle inserted and injection carried out following air ejection. A similar procedure occurs in U.S. Pat. No. 3,595,439 A for a mixing cartridge for dental two-component material.
GB 1 453 591 describes an ampoule, which has a perforatable sealing plug for a liquid chamber and an intermediate plug for a powder chamber. On needle perforation, e.g. connected to a drop, the intermediate plug is ejected, so that the two media can mix with one another. The mixture can then pass through an extra channel into the drop chamber.
JP 8-280907 A discloses an adapter, which has a liquid chamber sealed by an aluminum foil and which can be mounted on a container with a freeze-dried pharmaceutical. On the other side of the adapter sealed with a screw cap can be engaged a pump atomizer, which with its suction tube perforates the aluminum foil and thus interconnects the liquid chamber and powder container. This dispenser which has to be assembled from three separate parts prior to use is not very helpful for uncomplicated use purposes.
The problem of the invention is to provide a method and a dispenser for the application of two different media with which solid media can also be applied reliably, as well as in dosed, planned manner.
The invention provides a method in which a liquid is used as the carrier medium for the particulate solid medium and the separately stored media are only mixed together prior to their application. The term particulate solid medium is understood to mean that it is not in the form of a gas, liquid, paste or massive form, but instead normally dry with a certain flowability or free-flow capability and is in particular pulverulent or granular. Thus, it is possible to store the two media separately from one another and the active substance can be present in dry form usually in the particulate medium. It can e.g. be a pharmaceutical product in the form of a freeze-dried powder. Only just prior to application is it mixed with a liquid serving as the carrier medium. Either a suspension (dispersion) or also a solution can be obtained, which are then jointly applied, preferably as a spray mist, but also in drop or jet form.
Apart from the advantage that the product can be kept better in the dry powder form, the advantage also arises that the liquid can be so chosen that the absorption by the mucosa is particularly aided. There is no need for preservatives.
The particulate solid medium should preferably be pulverulent, but at least flowable or free-flowing and readily mixable with the liquid, so that in the relatively short available an intimate mixing or dissolving in the liquid is possible. However, it is also possible for the particles to be present in the form of so-called microcapsules, i.e. comprising the contents covered by a skin.
The direct and very immediate application following mixing is possible if the liquid is introduced into the solid medium under an application pressure and the resulting mixture is discharged under said application pressure. However, it is also possible to carry out mixing in a mixing phase directly upstream of the discharge or application. This e.g. makes it possible to ensure that firstly all the liquid is introduced into the chamber containing the solid medium prior to the start of application. In the case of particularly solution-active mixtures this can ensure a dissolving, or at least a good suspension of the solid medium in the liquid. The liquid acts as a carrier for the solid, but can itself have or contribute to pharmaceutical actions.
Advantageously between the mixing phase and the application phase there is a pressure point which has to be manually overcome for the actuating force, so that automatically there is a certain intermediate stop. The solid medium will not usually completely fill the chamber in which it is stored, which will contain an in part relatively large volume fraction of gas, e.g. air or also an inert gas aiding product stabilization. On mixing said gas can be compressed on introducing the liquid, so that finally on application, i.e. the opening of the solid reservoir or a mixing chamber there is already a certain initial pressure, which e.g. ensures a good atomization from the outset.
In addition, a dispenser is proposed, which has a liquid chamber, pressurizing means for producing an application pressure and for delivering liquid into a medium reservoir, separate from the liquid chamber, for a pulverulent or free-flowing solid medium and a discharge orifice for the mixture. The pressurizing means can be a thrust piston pump, whose cylinder can be the liquid chamber.
Prior to the actuation of the dispenser it is possible to keep the liquid chamber and the medium reservoir tightly sealed with respect to one another and the outside and only to connect the same with one another and to the discharge orifice through actuation. This can take place by perforating membrane-like pistons or container walls, by lip valves or the like.
The building up of pressure points, which permit the build-up of certain minimum actuating forces can take place both prior to the start of actuation and also between the mixing and application phase, e.g. by snap connections, but preferably by preset breaking points, i.e. material bridges which can be destroyed by actuating forces.
In the case of dispensers, which have a separate container for each application charge discharged all at once or in a few successive actuations, the opening of a medium chamber usually takes place by a thin, hollow needle, e.g. a steel needle, which is sharpened by a bevel and usually has a very small diameter below 1 mm. It is received in a shaft, which usually also presses the perforatable piston into the cylinder. In order to receive this thin, sensitive needle, it has hitherto been provided with a metal adapter, which was externally fitted to the needle as a relatively thick, solid, metal ring. It permitted an engagement of an assembly tool and was pressed into the shaft by means of an annular locking tooth system (cf. WO 96/24439). This arrangement has proved satisfactory and was considered unavoidable due to the reliable assembly without damaging the sensitive tip. However, it requires the metal adapter as a separate part, which increases costs and also the metal fraction in the dispenser which can otherwise be disposed of virtually in type-pure manner.
It has now been found that it is possible to fit the very thin and sensitive needle in damage-free manner with the necessary sealing action without said adapter. For this purpose it is introduced between the entire central area between the ribs of a larger bore in the shaft embracing both ends of the needle and at the end is pressed with press fit into a bore, which is somewhat longer than the needle diameter. It is supported on a shoulder within said bore and can consequently freely communicate to the discharge orifice. On insertion the needle is held at its end carrying the tip by a collet, which has a central pin engaging in the needle and consequently preventing a crushing and damage to the sensitive tip. This is important, because damage-free tips are necessary for the perforation of the closing plug in the same way as in a hypodermic needle, so as to avoid the needle detaching particles from the container or piston wall on penetrating the same and which would lead to a clogging of the discharge orifice or could even enter the respiratory tracts of the patient.
These and further features can be gathered from the claims, description and drawings and the individual features, both singly or in the form of sub-combinations, can be implemented in an embodiment of the invention and in other fields and can represent advantageous, independently protectable constructions for which protection is hereby claimed. The subdivision of the application into individual sections and the subtitles in no way restrict the general validity of the statements made thereunder.